Image forming apparatus with a removable holder for holding developing devices

ABSTRACT

An image forming apparatus is provided which includes a housing, a series of photoconductors on which an electrostatic latent image is formed, and developing devices, which each include a developing agent carrier for holding a developing agent. Also, the apparatus may include a holder, which is removable from the housing, for supporting the photoconductors and the developing devices, and an image reader provided at a top portion of the housing, which is configured to read an image on a document.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of prior U.S. application Ser. No.11/317,171, filed Dec. 27, 2005, which claims priority from JapanesePatent Application No. 2004-378084, filed Dec. 27, 2004, the entiresubject matter of which is incorporated herein by reference.

TECHNICAL FIELD

Aspects of the invention relate to an image forming apparatus thattransfers onto a recording medium a visible image formed by developingan electrostatic latent image with a developing agent.

BACKGROUND

Known image forming apparatuses form an image on a recording medium,such as a sheet, by forming an electrostatic latent image on an imagecarrying member and developing the electrostatic latent image with adeveloping agent. In such an image forming apparatus, a cartridgeincluding the image carrying member and a developing device, or a beltunit for conveying a sheet are removably set in a main housing of theimage forming apparatus, to enable the maintenance of the image formingapparatuses or a sheet jam clearing operation to be performed.

To remove the cartridge or the belt unit from the main housing, thecartridge or the belt unit is vertically pulled. For example, JapaneseLaid-Open Patent Publication No. 2004-206071 discloses a method toremove the belt unit from an upper portion of the image formingapparatus and the cartridge from a front face of the image formingapparatus.

In some image forming apparatuses, the cartridge or the belt unit ishorizontally disposed and is pulled horizontally from the main housing.Japanese Laid-Open Patent Publication No. 2003-015378 discloses an imageforming apparatus in which the cartridge is horizontally movable.

In the image forming apparatus disclosed in Japanese Laid-Open PatentPublication No. 2004-206071, the belt unit and the cartridge areseparately removable from and installable in the image forming apparatusresulting in good maintainability. However, when the belt unit is pulledout from the upper portion of the image forming apparatus, a relativelystrong force is required to remove the belt unit from the image formingapparatus.

In the image forming apparatus disclosed in Japanese Laid-Open PatentPublication No. 2003-015378, the cartridge is horizontally moved toremove it from the main housing of the image forming apparatus. Thus,the cartridge can be removed from the image forming apparatus with alighter force. However, in this image forming apparatus, the cartridgeand the belt unit are not individually accessible. Therefore, thecartridge has to be drawn out from the main housing first, for example,before the belt can be replaced, which leads to a complicatedreplacement operation and results in poor maintainability.

SUMMARY

Aspects provide an image forming apparatus with good maintainability.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative aspects will be described in detail with reference to thefollowing figures wherein:

FIG. 1 is a sectional side view of a general configuration of a printeraccording to an illustrative aspect;

FIG. 2 is a schematic showing a cartridge, a belt holder and a sheettray withdrawn from the printer according to an illustrative aspect;

FIG. 3 is a schematic showing the cartridge withdrawn from the printeraccording to an illustrative aspect;

FIG. 4 is a schematic showing the belt holder withdrawn from the printeraccording to an illustrative aspect; and

FIGS. 5A and 5B are side sectional views of a general configuration of amulti-function device according to other illustrative aspects.

FIG. 6 is a view of a general configuration of a multi-function devicewhere the scanner includes a document feeder according to anotherillustrative aspect.

FIG. 7 is a side sectional view of a general configuration of amulti-function device according to another illustrative aspect.

FIG. 8 is a side sectional view of a general configuration of amulti-function device according to another illustrative aspect.

FIG. 9 is a side sectional view of a general configuration of amulti-function device according to another illustrative aspect.

DETAILED DESCRIPTION

General Overview

In aspects, an image forming apparatus may include a housing; aphotoconductor on which an electrostatic latent image is formed, thephotoconductor being supported by a supporting shaft; developingdevices, each including at least a developing agent chamber configuredto include a developing agent and a developing agent carrier configuredto hold the developing agent thereon; a transfer device configured totransfer the visible image formed on the photoconductor to a recordingmedium; a first holder configured to hold the developing devices along afirst direction perpendicular to the supporting shaft of thephotoconductor, the first holder being placed in a first area in thehousing; a first guide configured to guide the first holder in and outof the first area in the first direction; a second holder configured tohold at least a belt member and a roller for supporting the belt member,the second holder being placed in a second area in the housing; and asecond guide configured to guide the second holder in and out of thesecond area in a second direction parallel to the first direction.

In the image forming apparatus with such a structure, the developingdevices may be held by the first holder. The first holder may be guidedby the first guide, such that the first holder may be removably set inthe housing. Therefore, the developing devices may be readily removedfrom or set in the first holder, leading to improvement ofmaintainability. Similarly, the second holder holding the belt membermay be moved such that the second holder may be removably set in thehousing. Thus, the setting or removal of the belt member may befacilitated.

Further, in the image forming apparatus, the first holder and the secondholder may be drawn in a direction perpendicular to the supporting shaftfor supporting the photoconductor. Therefore, a space may not berequired on a side to which the supporting shaft is drawn (i.e., a largehole may not have to be formed in a frame for supporting the supportingshaft). Thus, the supporting shaft may be stably supported and therigidity of the image forming apparatus may be increased.

In aspects of the image forming apparatus, the first holder and thesecond holder may be independently moved by the first guide and thesecond guide, respectively.

The developing devices and the belt member may be individually removedfor replacement. Therefore, time and trouble may be saved as comparedwith a case where the developing devices are first removed and then thebelt member is removed. Thus, maintainability may be improved.

In another aspect of the image forming apparatus, the first guide andthe second guide may make the photoconductor and the belt member contactwith each other when the first holder and the second holder are placedin the first area and the second area, respectively. The first guide andthe second guide may separate the photoconductor and the belt memberfrom each other while the first holder and the second holder are movedto the first drawing position and the second drawing position,respectively.

By moving the first holder and the second holder relative to the housingalong the first guide and the second guide, respectively, thephotoconductor and the belt member may make contact with each other orbe separated from each other. Therefore, a mechanism for contacting orseparating the photo conductor and the belt member may not have to beprovided in the image forming apparatus, leading to simple structures.Accordingly, costs of the image forming apparatus may be reduced. Inaddition, a user may removably set the first holder and the secondholder readily and promptly. Thus, the image forming apparatus with easeof use may be provided.

In certain aspects, the image forming apparatus may further include afirst cover for covering the first area; and a second cover for coveringthe second area. The first cover may be configured to be moved and thesecond cover may be configured to be moved relative to the first cover.

When the first holder or the second holder is removed, the first areaand the second area may be covered by the first cover and the secondcover, respectively. Therefore, such a case may be prevented that theimage forming apparatus may topple over when both first holder and thesecond holder are removed at a time. As compared with a case where theareas are exposed, exposure to dust or debris may be prevented. Thus,deterioration of the image forming apparatus or an image may beprevented.

In some aspects, the image forming apparatus may further include a sheetcontainer configured to include the recording medium before an image isformed, the sheet container being configured to be attachable to andremovable from the housing; and a third guide configured to guide thesheet container in a third direction parallel to the first direction.

The image forming apparatus may be provided with the sheet containerconfigured to include a recording medium before an image is formed. Thesheet container may be configured to be attachable to and removable fromthe housing in the same direction as the first direction. Thus, theimage forming apparatus with ease of use and good maintainability may beprovided. Further, spaces for removably setting the first and secondholders and the sheet container may be provided only on the same oneside of the image forming apparatus. Thus, limitations on installationof the image forming apparatus may be reduced.

In other aspects, the image forming apparatus may further include animage reading device configured to read an image and generate imagedata, the image reading device being disposed at an upper portion of thehousing; and an electrostatic latent image forming device configured toform the electrostatic latent image on the photoconductor based on theimage data generated by the image reading device.

With such a structure, an image on a recording medium may be read andthen formed. Thus, the image forming apparatus with ease of use may beprovided. When the image reading device is disposed at an upper portionof the housing, rigidity may be required for the image formingapparatus. However, in the above-described structures, rigidity of theimage forming apparatus may be improved, so that rigidity of the imageforming apparatus may be maintained even when the image reading deviceis disposed an upper portion of the housing.

In another aspect, the image forming apparatus may further include adischarging portion configured to discharge the recording medium onwhich the image is formed. The discharging portion may be disposedbetween the image reading device and the housing.

A discharging portion configured to discharge the recording medium onwhich the image is transferred may be disposed between the image readingdevice of the image forming apparatus and the image forming apparatus.Therefore, the discharging portion may not protrude or stand out in theimage forming apparatus, as compared with a case where the dischargingportion is disposed on one side of a front or rear end, or a left orright end of the housing of the image forming apparatus. Thus, the spacemay be saved.

Illustrative Aspects

Illustrative aspects will be described with reference to theaccompanying drawings. FIG. 1 is a sectional side view of a generalconfiguration of a printer 10 according to an illustrative aspect. Theleft and right sides in FIG. 1 are defined as front and rear sides ofthe printer 10.

As shown in FIG. 1, the printer 10 is a so-called tandem color laserprinter. The printer 10 includes a housing 10 a, a visible image formingunit 11, a belt unit 50, a fixing unit 60, a sheet supplying unit 70, asheet output tray 80, and an exposure device 35.

According to visible image forming processes with developing agents ofmagenta (M), cyan (C), yellow (Y), and black (Bk) toner, the visibleimage forming unit 11 is provided with developing devices 31M, 31C, 31Y,31Bk, organic photoconductive (OPC) drums 32M, 32C, 32Y, 32Bk, asphotoconductors, cleaning rollers 33M, 33C, 33Y, 33Bk, and chargers 34M,34C, 34Y, 34Bk.

The developing devices 31M, 31C, 31Y, 31Bk include developing rollers36M, 36C, 36Y, 36Bk, respectively. A roller portion of each of thedeveloping rollers 36M, 36C, 36Y, 36Bk is formed of a conductivesilicone rubber. A surface of the roller portion of the developingroller 36M, 36C, 36Y, 36Bk is coated with resin or rubber includingfluorine. The roller portion of the developing roller 36M, 36C, 36Y,36Bk may be formed of, for example, urethane rubber. The ten pointheight (Rz) of the surface of the developing roller 36M, 36C, 36Y, 36Bkis set to about 3-5 m, which is smaller than the average toner particlesize of about 9 μm.

The developing devices 31M, 31C, 31Y, 31Bk also include supply rollers37M, 37C, 37Y, 37Bk, respectively. A roller portion of each supplyroller 37M, 37C, 37Y, 37Bk is formed of a conductive sponge. The supplyroller 37M, 37C, 37Y, 37Bk is disposed so as to press against therespective developing roller 36M, 36C, 36Y, 36Bk with an elastic forceof the sponge. For the roller portions of the supply rollers 37M, 37C,37Y, 37Bk, foaming materials, such as conductive silicone rubber, EPDM(Ethylene Propylene Diene Monomer), and urethane rubber can be used.

The developing devices 31M, 31C, 31Y, 31Bk are provided withlayer-thickness regulating blades 38M, 38C, 38Y, 38Bk, respectively.Each layer-thickness regulating blade 38M, 38C, 38Y, 38Bk has astainless steel blade formed into a plate shape whose one end is fixedto the respective developing device case 39M, 39C, 39Y, 39Bk. The otherend of the stainless steel blade is provided with a pressing portionformed of insulating silicone rubber, insulating rubber or resinincluding fluorine. The pressing portion of the blade 38M, 38C, 38Y,38Bk is pressed against the respective developing roller 36M, 36C, 36Y,36Bk from above.

Each of the organic photoconductive (OPC) drums 32M, 32C, 32Y, 32Bk isformed of, for example, an aluminum base on which a positivelychargeable photoconductive coating layer is formed. The thickness of thepositively chargeable photoconductive coating layer is set to 20 μm ormore. The aluminum base is used as a ground layer. The OPC drums 32M,32C, 32Y, 32Bk are arranged in manner such that they are parallel to thedischarge direction described below.

A roller portion of each cleaning roller 33M, 33C, 33Y, 33Bk is formedof an elastic material, such as a conductive sponge. The cleaningrollers 33M, 33C, 33Y, 33Bk slide on the respective OPC drums 32M, 32C,32Y, 32Bk at positions obliquely below the OPC drums 32M, 32C, 32Y,32Bk.

Each charger 34M, 34C, 34Y, 34Bk is a scorotron charger. The chargers34M, 34C, 34Y, 34Bk are disposed downstream of the respective cleaningrollers 33M, 33C, 33Y, 33Bk with respect to a rotating direction of theOPC drums 32M, 32C, 32Y, 32Bk, so as not to contact the OPC drums 32M,32C, 32Y, 32Bk.

The exposure device 35 is composed of a known scanner unit and disposedabove the visible image forming unit 11. Surfaces of the OPC drums 32M,32C, 32Y, 32Bk uniformly charged by the respective chargers 34M, 34C,34Y, 34Bk are exposed to the laser light with the exposure device 35 inaccordance with image data, to form an electrostatic latent imagecorresponding to each color on the relevant OPC drums 32M, 32C, 32Y,32Bk.

The positively charged toner is supplied from the supply rollers 37M,37C, 37Y, 37Bk to the respective developing rollers 36M, 36C, 36Y, 36Bk.The toner is carried on the developing rollers 36M, 36C, 36Y, 36Bk as athin layer whose thickness has been regulated by the respective blades38M, 38C, 38Y, 38Bk.

By supplying positively charged toner to positively chargedelectrostatic latent images formed on the OPC drums 32M, 32C, 32Y, 32Bkby the exposure device 35, reverse development is achieved at contactpositions between the developing rollers 36M, 36C, 36Y, 36Bk and therespective OPC drums 32M, 32C, 32Y, 32Bk. Thus, a high-quality image canbe formed.

The belt unit 50 includes a conveying belt 58, and a drive roller 51 anda driven roller 52 that wind the conveying belt 58 therearound. Thedrive roller 51 is driven by a motor (not shown) so as to rotate andaccordingly the driven roller 52 rotates. Thus, the rotating belt 58 iscirculated. The conveying belt 58 is an endless belt formed of resinmaterial, such as conductive polycarbonate and polyimide, in whichconductive powders, such as carbon, are dispersed. Each of transferrollers 53 is disposed near a position where one of the OPC drums 32M,32C, 32Y, 32Bk face the conveying belt 58.

A sheet P supplied from the sheet supplying unit 70 via a pickup roller72 is fed by the conveying belt 58 of the belt unit 50 so as to passbetween the conveying belt 58 and the OPC drums 32M, 32C, 32Y, 32Bk.While the sheet P is conveyed, the toner image carried on each OPC drum32M, 32C, 32Y, 32Bk is sequentially transferred onto the sheet P to forma color image on the sheet P.

A cleaning unit 55 is disposed at a position opposite the OPC drums 32M,32C, 32Y, 32Bk with respect to the conveying belt 58. The cleaning unit55 includes a scraping member 56 and a case 57. Toner or debris attachedto the conveying belt 58 is scraped by the scraping member 56 andcollected to the case 57.

The fixing unit 60 includes a heat roller 61 and a pressing roller 62that rotate while contacting each other. The heat roller 61 is providedtherein with a heater 63 such as a halogen lamp that generates heat byapplying power to heat the heat roller 61. A temperature sensor 64, suchas a thermistor that detects surface temperatures of the heat roller 61is disposed so as to contact the surface of the heat roller 61. In thefixing unit 60, the toner images transferred onto the sheet P arethermally fixed to the sheet P with the application of heat and pressurewhile the sheet P is held between the pressing roller 62 and the heatroller 61 whose temperature is controlled during the printing operationto a fixing temperature of, for example, about 180 degrees.

The sheet supplying unit 70 is disposed at a bottom portion of thehousing 10 a. The sheet supplying unit 70 includes a sheet tray 71, as acassette, that accommodates the sheets P, and the pickup roller 72 thatpicks up and feeds the sheets P. The sheet supplying unit 70 suppliesthe sheet P by adjusting a timing with image forming processes with theexposure device 35, the developing devices 31M, 31C, 31Y, 31Bk, and theOPC drums 32M, 32C, 32Y, 32Bk. The sheet P supplied from the sheetsupplying unit 70 is fed to a contact portion between the conveying belt58 and a first feed roller 54.

The sheet output tray 80 is disposed downstream of the fixing unit 60 inthe sheet feeding direction. The sheet P fed from the fixing unit 60 isdischarged (output) to the sheet output tray 80 via pairs of feedrollers 91, 92, 93 in a direction (discharge direction) substantiallyparallel to a horizontal direction when the multi-function device 13 isplaced on a flat surface for operation.

Operations of the printer 10 will be described below. While the OPCdrums 32M, 32C, 32Y, 32Bk are rotated, the photoconductive coatinglayers on the surfaces of the OPC drums 32M, 32C, 32Y, 32Bk areuniformly charged by the respective chargers 34M, 34C, 34Y, 34Bk. Thephotoconductive coating layers are exposed to the laser light with theexposure device 35 in association with an image of each color ofmagenta, cyan, yellow, and black. Magenta, cyan, yellow, and black toneris applied by the relevant developing devices 31M, 31C, 31Y, 31Bk to theelectrostatic latent images formed on the photoconductive coating layersof the OPC drums 32M, 32C, 32Y, 32Bk. Thus, development of magenta,cyan, yellow, and black color is performed. Color toner images, asdeveloping agent images, formed on the photoconductive coating layers ofthe OPC drums 32M, 32C, 32Y, 32Bk are transferred on the sheet Pconveyed by the conveying belt 58. Exposure timing is determined basedon a moving speed of the conveying belt 58 that conveys the sheet P andthe distance between the OPC drums 32M, 32C, 32Y, 32Bk. The respectivecolor toner images are transferred on the sheet P so as to integrate thecolor image on the sheet P. Toner remaining on the OPC drums 32M, 32C,32Y, 32Bk after the toner images have been transferred on the sheet P istemporarily caught by the cleaning rollers 33M, 33C, 33Y, 33Bk.

Toner images of four colors transferred on the sheet P while the sheet Pis fed along the conveying belt 58 are thermally fixed on the sheet P inthe fixing unit 60. Then, the sheet P is output to the sheet output tray80. Thus, a color image is formed on the sheet P.

As shown in FIG. 2, the visible image forming unit 11 is held in acartridge 30, as a first holder. The belt unit 50 is held in a beltholder 59, as a second holder. The cartridge 30 and the belt holder 59are removably installed in the housing 10 a separately. Thus, thevisible image forming unit 11 and the belt unit 50 can be removablyinstalled in the printer 10 readily.

The sheet tray 71 of the sheet supplying unit 70 is removably installedin the housing 10 a along the same direction that the cartridge 30 andthe belt holder 59 are removably installed in the housing 10 a. Thus,ease of use can be improved.

The cartridge 30, the belt holder 59, and the sheet tray 71 will bedescribed in detail below, with reference to FIG. 2.

Engagement portions (not shown) for holding the developing device cases39M, 39C, 39Y, 39Bk are provided in the cartridge 30. The cartridge 30removably holds the developing device cases 39M, 39C, 39Y, 39Bk byengaging engaged portions (not shown) provided in the developing devicecases 39M, 39C, 39Y, 39Bk, with the engagement portions of the cartridge30.

A pair of projecting members 100 is provided in the cartridge 30 at itsright and left ends in FIG. 2. Four supporting members 100 a thatrotatably support shafts of the OPC drums 32M, 32C, 32Y, 32Bk areprovided in the cartridge 30.

A pair of the supporting members 104 for rotatably supporting shafts ofthe drive roller 51 and the driven roller 52 is disposed in the beltholder 59.

A pair of projecting members 108 is disposed in the sheet tray 71.

Provided in the housing 10 a are guide mechanisms 115, 116, 117, asfirst, second, and third guides, respectively. The guide mechanism 115is provided with guide grooves 101 for guiding the projecting members100 and the supporting members 100 a provided in the cartridge 30 intothe housing 10 a substantially horizontally from a front side of theguide mechanism 115 (from the left side in FIG. 2).

Similarly, the guide mechanism 116 is provided with a guide groove 105for guiding the supporting members 104 provided in the belt holder 59into the housing 10 a substantially horizontally from a front side ofthe guide mechanism 116 (from the left side in FIG. 2).

The guide mechanism 117 is provided with a guide groove 109 for guidingthe projecting members 108 provided in the sheet tray 71 into thehousing 10 a substantially horizontally from a front side of the guidemechanism 117 (from the left side in FIG. 2).

Stopper members 103 for elastically stopping and positioning theprojecting members 100, 108 and the supporting members 100 a, 104 areprovided on each guide groove 101, 105, 109.

With the above-described structures, the cartridge 30, the belt holder59, and the sheet tray 71 are inserted into the housing 10 a with theaid of the guide mechanism 115, 116, 117 along the guide grooves 101,105, 109. At an accommodation portion where the cartridge 30, the beltholder 59, and the sheet tray 71 are properly placed in the housing 10a, as shown in FIG. 1, the projecting members 100, 108 and thesupporting members 100 a, 104 are positioned by the stopper member 103.When the cartridge 30, the belt holder 59, and the sheet tray 71 aredrawn from the housing 10 a, the projecting members 100, 108 and thesupporting members 100 a, 104 are pulled out from the accommodationportion by the application of force opposing the elastic force of thestopper members 103. Then, the cartridge 30, the belt holder 59, and thesheet tray 71 are removed from the housing 10 a along the relevant guidegrooves 101, 105, 109 in a direction substantially parallel to ahorizontal direction when the multi-function device 13 is placed on aflat surface for operation and substantially parallel to the directionin which a sheet is discharged to the output tray 80. For example, theremoval directions of the cartridge 30, the belt holder 59 and the sheettray 71 may be within 5 degrees of the sheet discharge direction.

It will be understood that “substantially parallel” as described hereinrefers to two lines, planes or directions being within 5 degrees of eachother.

By sliding the cartridge 30 and the belt holder 59 along the guidegrooves 101, 105, respectively, the cartridge 30 and the belt holder 59can be completely removed from the housing 10 a. A first drawingposition corresponds to a position where the cartridge 30 is about to beremoved from the housing 10 a (a position immediately before thecartridge 30 is removed out from the housing 10 a). A second drawingposition corresponds to a position where the belt holder 59 is about tobe removed from the housing 10 a (a position immediately before the beltholder 59 is removed from the housing 10 a).

To prevent the OPC drums 32M, 32C, 32Y, 32Bk from being damaged bycontacting the conveying belt 58 when the cartridge 30 or the beltholder 59 are removably installed in the housing 10 a, the guide grooves101, 105 are structured to bring the OPC drums 32M, 32C, 32Y, 32Bk intocontact with the conveying belt 58 when the projecting members 100 andthe supporting members 100 a, 104 reach the accommodation portion wherethe cartridge 30 and the belt holder 59 are placed in position in thehousing 10 a.

When the projecting members 100 and the supporting members 100 a, 104are removed from the accommodation portions, the OPC drums 32M, 32C,32Y, 32Bk are moved away or spaced apart from the conveying belt 58.

The guide mechanisms 115, 116, 117 are individually provided in thehousing 10 a, such that the cartridge 30, the belt holder 59, and thesheet tray 71 can be individually installed in or removed from thehousing 10 a in a direction substantially parallel to each other.

To allow the cartridge 30 and the belt holder 59 to be removablyinstalled in the housing 10 a, a front lower cover 82, as a secondcover, is pivotally disposed about a supporting shaft 84 at a front sideof the housing 10 a so as to open or close, and a front cover 81, as afirst cover, is pivotally disposed about a supporting shaft 83 on thefront lower cover 82.

As shown in FIG. 3, as the front cover 81 is opened, the cartridge 30can be removed from the housing 10 a. As shown in FIG. 4, as the frontlower cover 82 is opened together with the front cover 81, the beltholder 59 can be removed from the housing 10 a. It will be appreciatedthat the front cover 81 and the front lower cover 82 may be replaced bya single front cover.

When a handle 85 is pulled toward the front side of the housing 10 a,the sheet tray 71 can be removed from the housing 10 a.

In the printer 10, components of the visible image forming unit 11 areintegrally contained in the cartridge 30. By sliding the cartridge 30along the guide mechanism 115 provided in the housing 10 a, thecartridge 30 can be readily installed in or removed from the housing 10a. Similarly, by sliding the belt holder 59 and the sheet tray 71 alongthe guide mechanism 116, 117, the belt holder 59 and the sheet tray 71can be readily installed in or removed from the housing 10 a. Thus, thecartridge 30, the belt holder 59, and the sheet tray 71 can be readilyinstalled in or removed from the housing 10 a, leading to theimprovement of the maintainability of the printer 10.

Because a removing or drawing direction of the cartridge 30, the beltholder 59, and the sheet tray 71 is substantially horizontal, thecartridge 30, the belt holder 59, and the sheet tray 71 can be drawnwith a lighter force. When the cartridge 30 and the belt holder 59 areplaced in position by the guide mechanisms 115, 116, a fine qualityimage can be formed.

Further, as the sheet tray 71 is placed in position by the guidemechanism 117, the sheet P can be supplied from the tray 71 properly.

Because the cartridge 30, the belt holder 59, and the sheet tray 71 canbe drawn in the same direction, their handling can be facilitated andmaintainability can be improved. Further, spaces for removably settingthe cartridge 30, the belt holder 59, and the sheet tray 71 may beprovided on the same side of the housing 10 a. Thus, limitations oninstallation of the components of the printer 10 can be reduced.

For example, if the cartridge 30, the belt holder 59, and the sheet tray71 are drawn in an axial direction of a roller of the housing 10 a, suchas the OPC drum 32M, 32C, 32Y, 32Bk, a relatively large hole needs to beformed in a frame for supporting a shaft of the roller. Accordingly, therigidity of the printer 10 is reduced. However, in illustrative aspectsof the invention, the cartridge 30, the belt holder 59, and the sheettray 71 can be drawn in a substantially horizontal directionperpendicular to an axial direction of a roller. Therefore, an increasein rigidity of the printer 10 can be achieved because it is unnecessaryto form a hole in the frame.

If such a structure is employed that various rollers are drawn alongtheir axial direction, bearings for receiving or supporting the rollersneed to be withdrawn, so that positioning the bearings becomesdifficult, resulting in complicated structures. However, the printer 10can avoid having such difficult structures.

Referring to FIGS. 5A and 5B, a multi-function device 13, according toother aspects of the invention, including a scanner, as an image readingdevice, will be described below.

In the multi-function device 13, as shown in FIGS. 5A and 5B, a scanner120 is disposed above the printer 10 and together with the printer 10 inthe housing 10 a, parallel to the bottom of the housing 10 a. Thescanner 120 includes a table 121 made of a transparent material such asplaten glass for receiving a document to be scanned, an optical system126, positioned below the table 121, for transmitting light toward thetable 121 when a scanning operation occurs, a carrier 127 for moving theoptical system 126 to scan the document in a direction substantiallyperpendicular to the discharge direction, a cover 123 for covering thetable 121, a hinge 125 for coupling the cover 123 to the table 121,where the hinge allows the cover 123 to move between an open positionand a closed position. In an illustrative example, the direction inwhich the carrier 127 moves the optical system 126 may be between 85 and95 degrees away from the discharge direction associated with the sheetoutput tray 80. The scanner 120 is provided with a control panel 122,which may be coupled to the table 121, including an operation portion124 for operating the scanner 120 and the printer 10. A sheet outputtray 80 for receiving the sheets P output from the printer 10 isdisposed between the scanner 120 and the printer 10. In themulti-function device 13, the scanner 120 is disposed at an upperportion of the multi-function device 13. With such a structure, imagescanning and printing can be readily performed. Thus, the multi-functiondevice 13 can be provided with good usability.

FIG. 6 shows a multi-function device 13 with a document feeder as partof the cover 123. The document feeder includes an input tray 130, apickup roller 132, roller pairs 134 a, 134 b, discharge roller pair 134c and output tray 135. In one form of operation of the scanner 120, adocument to be scanned is handled by the document feeder as follows. Thedocument is placed in the input tray 130 and is drawn into the scanningpath 131 by the pickup roller 132. The pickup roller 132 transports thedocument along the scanning path 131 to a first pair of rollers 134 a.The first pair of rollers 134 a passes the document by the opticalsystem 126 for scanning to the second pair of rollers 134 b. The secondroller pair 134 b passes the document to the discharge roller pair 134c, which discharges the document to the output tray 135 in the scanningdischarge direction. The scanning discharge direction is substantiallyperpendicular to the discharge direction in which a sheet is dischargedto the sheet output tray 80 described previously. For example, thescanning discharge direction may be between 85 and 95 degrees away fromthe discharge direction associated with the sheet output tray 80.

The scanner 120 is disposed in the top portion of the housing 10 asubstantially parallel to the bottom of the housing 10 a, that is,substantially horizontally. Accordingly, when the cartridge 30 isremoved, the cartridge 30 can be smoothly drawn without interferencefrom the scanner 120.

The sheet output tray 80 is disposed between the printer 10 and thescanner 120. Because the sheet output tray 80 is provided in themulti-function device 13 so as not to project or stand out, the spaceoccupied by the multi-function device 13 can be reduced.

The control panel 122 including the operation portion 124, which isoperated by a user, is disposed in the scanner 120 at an upper part ofthe multi-function device 13. In one illustrative implementation asshown, the control panel 122 may slope away from the front end of thetable 121 toward the side of the housing 10 a from which the cartridge30 may be removed. In this example, the control panel 122 need notextend to reach the side of the housing 10 a from which the cartridge 30may be removed; rather the control panel 122 may be behind this portion.With the structure, the control panel 122 can be readily operated, ascompared with a scenario where the control panel 122 is disposed on afront surface of the housing 10 a. For example, the control panel 122 isoriented such that the user may easily read and operate themulti-function device 13.

FIG. 5B is provided to show an alternate configuration of the scanner120, where the rear end of the table 121 is located in a differentposition, namely, between a portion of the housing 10 a from where thecartridge 30 is removable and a portion opposite that portion of thehousing 10 a, where a line connecting the portions is parallel to thetable 121. With such an arrangement the cover 123 may be opened passedthe vertical position as shown in FIG. 5B when the rearmost portion ofthe housing 10 a of the multi-function device 13 is located up againstor very close to a flat surface such as a wall.

FIG. 7 is an alternate multi-function device 13 implementation which ismodified from FIG. 5A. In FIG. 7, the front cover 140 includes a builtin manual feed tray 142 that can be opened to receive a sheet for manualfeeding to the conveying belt 58 when the front cover 140 remains in aclosed position. When a sheet is placed in the manual feed tray 142 anda user requests a printing operation, pickup roller 144 draws the sheetfrom the manual feed tray 142 onto the conveying belt 58 for furtherhandling.

FIG. 8 is another alternate multi-function device 13 implementationwhich is modified from FIG. 5A. The multi-function device 13 of FIG. 8has been configured to accommodate duplex printing. When a user requestsduplex operation, the first time that a sheet P passes through thefixing unit 60 to the feed rollers 91, 92 and 93, the sheet P does notget discharged to the output tray 80. Rather, a sensor 150 positioned,for example, near to the feed rollers 93 detects the leading edge of thesheet P. Once a predefined time period elapses following detection bythe sensor 50 (i.e., to allow the sheet P to clear the fixing unit 60and feed rollers 91), the feed rollers 92 and 93 are reversed, a guide152, which is movable between two positions (as shown) is set to guidethe sheet P to the duplex feeding path 154, which is located below thesheet tray 71. Rollers pairs 156 a, 156 b, 156 c in the duplex feedingpath transport the sheet P to the conveying belt 58 so that the secondside of the sheet P may be printed on. Once the sheet P clears thefixing unit 60 for the second time, it will then pass the feed rollers91, 92, 93 to be discharged to the output tray 80.

FIG. 9 is another alternate multi-function device 13 implementation. Thesheet supplying unit 70 is configured oppositely from FIGS. 5A and 5B.The pickup roller 72 is located away from the front cover opposite fromFIGS. 5A and 5B. The pickup roller 72 picks up and feed a sheet P to acontact portion between the intermediate belt 160 and a transfer roller162. The OPC drums 32M, 32C, 32Y, 32Bk contact the intermediate belt160, and are configured to transfer color toner images, as developingagent images, to the intermediate belt 160. When an image has beentransferred from the OPC drums 32M, 32C, 32Y, 32Bk to the intermediatebelt 160, the intermediate belt 160 with the aid of the transfer roller162 transfers the developing agent images from the belt 160 to the sheetP when the sheet P passes between the intermediate belt 160 and thetransfer roller 162. Thereafter, the fixing unit 60 operates asdescribed previously to affix the toner to the sheet P. Then, the sheetpasses through roller pair 93 for discharge to the output tray 80. Itwill be appreciated that the intermediate belt 160 can be removed fromthe housing 10 a in the same manners as described with respect to theconveying belt 58.

While this disclosure has been described in conjunction with theexemplary aspects outlined above, various alternatives, modifications,variations, improvements and/or substantial equivalents, whether knownor may be presently unforeseeable, may become apparent to those havingat least ordinary skill in the art. Accordingly, the exemplary aspectsof the disclosure, as set forth above, are intended to be illustrative,not limiting. Various changes may be made without departing from thespirit and scope of the disclosure. Therefore, the disclosure isintended to embrace all known or later developed alternatives,modifications, variations, improvements and/or substantial equivalents.

For example, in the above disclosure, the printer of a direct transfertype is described in which images are transferred directly from the OPCdrums 32M, 32C, 32Y, 32Bk, to the sheet P. However, the aspects of theinvention may be applied to a printer of an intermediate transfer typein which images are first transferred on an intermediate transfer beltand then on the sheet P.

In the above disclosure, the conveying belt 58 extends between two driveand driven rollers 51, 52 in one direction. However, the conveying belt58 may extend between three or more rollers in two or more directions.

In the above disclosure, the belt holder 59 is disposed below thecartridge 30. However, the belt holder 59 may be disposed above thecartridge 30. In this case, the developing device case 39 may openupward. Thus, leakage of the toner may be prevented.

In the above disclosure, when the cartridge 30 or the belt holder 59 isdrawn to a certain position, the cartridge 30 or the belt holder 59 isremoved from the housing 10 a, without being stopped during drawing.However, a stopper for stopping the cartridge 30/the belt holder 59 at acertain position may be provided to stop the drawing of the cartridge30/the belt holder 59.

1. An image forming apparatus comprising: a housing; a plurality ofphotoconductors on which an electrostatic latent image is formed; aplurality of developing devices, each including a developing agentcarrier for holding a developing agent thereon; a belt unit including abelt support roller, and a belt that is supported by the belt supportroller; a holder for supporting the plurality of photoconductors and theplurality of developing devices, the holder being removable from thehousing; a sheet container configured to accommodate a stack of sheets,the sheet container being removable from the housing; wherein thehousing further includes: a front cover provided at a front surface ofthe housing, the front cover being movable between an open position anda closed position; a first area, provided inside the housing, configuredto receive the holder when the front cover is in the open position; asecond area, provided inside the housing, configured to receive thesheet container; a first sheet path that extends between the holder andthe belt unit when the holder is received in the first area, the firstsheet path configured to guide a sheet to the plurality ofphotoconductors; and a sheet discharging portion that is coupled to thefirst sheet path and extends above the holder when the holder isreceived in the first area, the sheet discharging portion beingconfigured to transport the sheet from the plurality of photoconductorsand to discharge the sheet toward the front surface in a firstdirection; and wherein the holder further comprises a feed rollerconfigured to face the belt support roller with the belt contacting thefeed roller when the holder is received in the first area, the feedroller and the belt being cooperatively configured to receive the sheetfrom the sheet container and guide the sheet into the first sheet path,wherein the front cover comprises an opening configured to receive asheet for passage to the first sheet path, wherein the feed roller andthe belt support roller are cooperatively configured to receive thesheet from the opening and guide the sheet into the first sheet path,and wherein the holder is configured to be moved in an upward directioncausing the feed roller to be separated from the belt to allow theholder to be removed from the housing.
 2. The image forming apparatusaccording to claim 1, wherein the holder is configured to be removedfrom the first area through an opening in a second direction that issubstantially parallel to the first direction when the front cover is inthe open position.
 3. The image forming apparatus according to claim 2,wherein the sheet container is configured to be removed from the secondarea in a third direction that is substantially parallel to the firstdirection.
 4. The image forming apparatus according to claim 1, whereinthe belt unit is configured to be positioned between the holder and thesheet container when the holder is received in the first area and thesheet container is received in the second area, and, wherein the belt isconfigured to guide the sheet in the first sheet path.
 5. The imageforming apparatus according to claim 1, wherein the belt unit isconfigured to be removed from the housing without the holder beingremoved from the housing.
 6. The image forming apparatus according toclaim 5, wherein the housing further includes: a third area providedinside the housing, the third area configured to receive the belt unit.7. The image forming apparatus according to claim 6, wherein the beltunit is configured to be removed from the third area when the frontcover is in the open position.
 8. The image forming apparatus accordingto claim 5, wherein the belt unit is configured to be positioned betweenthe holder and the sheet container when the holder is received in thefirst area and the sheet container is received in the second area. 9.The image forming apparatus according to claim 8, wherein the housingfurther includes: a third area inside the housing, the third areaconfigured to receive the belt unit.
 10. The image forming apparatusaccording to claim 9, wherein the belt unit is configured to be removedfrom the third area when the front cover is in the open position and theholder is removed from the first area.
 11. The image forming apparatusaccording to claim 9, wherein the holder is configured to be removedfrom the first area in a second direction and the belt unit isconfigured to be removed from the third area in a third direction thatis substantially parallel to the second direction.
 12. The image formingapparatus according to claim 1, further comprises: a second sheet paththat extends under the first sheet path, the second sheet pathconfigured to guide the sheet from the sheet discharging portion to thefirst sheet path the first time the sheet enters the sheet dischargingportion in duplex operation.
 13. The image forming apparatus accordingto claim 12, wherein the second sheet path is provided below the sheetcontainer.
 14. The image forming apparatus according to claim 1, whereinthe housing further comprises: a guide groove along which the holder isguided when the holder is removed from the housing; and a stopper memberprovided on the guide groove and configured to move the holder in adownward direction so that the holder is received in the first area andconfigured to allow the holder to be removed from the first area whenthe holder is moved in the upward direction.
 15. An image formingapparatus comprising: a housing; a plurality of photoconductors on whichan electrostatic latent image is formed; a plurality of developingdevices, each including a developing agent carrier for holding adeveloping agent thereon; a belt unit including a belt support roller,and a belt that is supported by the belt support roller; a holder forsupporting the plurality of photoconductors and the plurality ofdeveloping devices, the holder being removable from the housing; a sheetcontainer configured to accommodate a stack of sheets, the sheetcontainer being removable from the housing; wherein the housing furtherincludes: a front cover provided at a front surface of the housing, thefront cover being movable between an open position and a closedposition; a first area, provided inside the housing, configured toreceive the holder when the front cover is in the open position; asecond area, provided inside the housing, configured to receive thesheet container; a third area provided inside the housing; the thirdarea configured to receive the belt unit, wherein the belt unit isconfigured to be removed from the third area when the front cover is inthe open position; a first sheet path that extends between the holderand the belt unit when the holder is received in the first area, thefirst sheet path configured to guide a sheet to the plurality ofphotoconductors; and a sheet discharging portion that is coupled to thefirst sheet path and extends above the holder when the holder isreceived in the first area, the sheet discharging portion beingconfigured to transport the sheet from the plurality of photoconductorsand to discharge the sheet toward the front surface in a firstdirection; and a first cover for covering the first area; and a secondcover for covering the third area, wherein the first cover is configuredto be moved and the second cover is configured to be moved relative tothe first cover, wherein the holder further comprises a feed rollerconfigured to face the belt support roller with the belt contacting thefeed roller when the holder is received in the first area, the feedroller and the belt being cooperatively configured to receive the sheetfrom the sheet container and guide the sheet into the first sheet path,and wherein the belt unit is configured to be removed from the housingwithout the holder being removed from the housing.
 16. The image formingapparatus according to claim 15, wherein the front cover furthercomprises: an opening configured to receive a sheet for passage to thefirst sheet path, wherein the feed roller and the belt support rollerare cooperatively configured to receive the sheet from the opening andguide the sheet into the first sheet path.